1. Field of the Invention
The present invention relates to a bed apparatus for an X-ray diagnostic apparatus having a safety function for preventing a patient from falling, an X-ray apparatus and a method of controlling a bed for an X-ray diagnostic apparatus.
2. Description of the Related Art
As for diagnosis using an X-ray diagnostic apparatus, in some cases, an operator lifts a bed at about 90° from a horizontal position to lift a patient. In such diagnosis, in related art, when lifting a bed from a horizontal position to lifting position, an operator operates the bed such that a patient does not fall forward, constantly watching the condition of the patient.
A technology, which prevents displeasure and discomfort of a patient due to rapid change in speed of a bed and the patient from falling forward by changing a moving speed of a bed with respect to its lifting angle such that the speed is high at the first half and low at the later half, has been proposed (for example, JP-UM-A No. 2-63817).
However, in methods of lifting a bed, for patients bent or with weak legs, when the lifting angle of a bed reaches about 90°, the patients may fall forward or feel uneasy as if they fall forward. Accordingly, while constantly watching the condition of a patient, an operator should pay attention to the operation of a bed as stopping a lifting operation of a bed, when the patient seems to fall forward.
According to the above technology disclosed in JP-UM-A-2-63817, because only the speed of a bed changes, when a patient seems to fall forward, an operator needs to stop the lifting operation of a bed. Therefore, an operator should constantly watch the condition of a patient.
Such problems appear not only in a bed apparatus used in an X-ray diagnostic apparatus, but a bed for other medical instruments.